WHAT IS AN INFECTIOUS DISEASE?

Carnivores eat their prey from the outside, author David Quammen writes in his 2012 book Spillover. Pathogens attack from within and are no less deadly. They enter our bodies unseen when we breathe, have sex, take a drink of water or just walk in the woods. and they are relentlessly opportunistic. Pathogens that cause about six out of 10 human diseases — including aIDS, influenza, cholera, malaria, tuberculosis and Ebola — infect animals such as birds, bats, cattle, monkeys, camels and other species. These microbes bring humans and animals together in a deadly exchange driven in part by shifting environmental conditions. Through a global initiative known as One Health, veterinary and human health organizations are coordinating research and sharing results. They are tracking pathogens wherever they go. Researchers at Oregon State University take a multipronged approach to these diseases. They are delving into the social and historical dimensions of disease transmission and medical science. In the face of growing resistance to antibiotics, they are developing new drugs, including antivirals. They are helping public-health agencies get the most from vaccination campaigns and efforts to combat outbreaks. While the nearly complete eradication of smallpox, polio and other diseases stands as a triumph of medicine and science, new threats are emerging. For example, climate change raises the possibility that malaria, eradicated in the United States in the early 1950s, could come back. and as the footprint of human development expands, pathogens such as the bacteria that cause Lyme disease proliferate along with their preferred host, the blacklegged tick. “It’s a race that humans cannot win,” says Luiz Bermudez, Oregon State professor of Veterinary Medicine. “Microbes grow too fast. They modify too fast. There are billions of them.” Our best chance, he says, is to disarm them without promoting resistance. By NICK HOUTMaN